Washington's net-metering law, enacted in 1998, applies to systems up to 100 kW that generate electricity using solar, wind, hydro, biogas from animal waste, or CHP technologies (including fuel cells). CHP systems are called net-metering systems defined to be a fuel cell, a facility that produces electricity and used and useful thermal energy from a common fuel source, or a facility for the production of electrical energy that generates renewable energy, and that:

Has an electrical generating capacity of not more than 100 kW.

Is located on the customer-generator's premises.

Operates in parallel with the electric utility's transmission and distribution facilities.

Is intended primarily to offset part or all of the customer-generator's requirements for electricity.

All customer classes are eligible, and all utilities -- including investor-owned utilities, municipal utilities and electric cooperatives -- must offer net-metering.

Net-metering is available on a first-come, first-served basis until the cumulative generating capacity of net-metered systems equals 0.25% of a utility's peak demand. This limit increased to 0.5% on January 1, 2014. At least one-half of the utility's available aggregate net-metering capacity is reserved for systems generating electricity using renewables.

Energy is measured with a single, bi-directional meter which the utility must provide. However, the customer is responsible for providing the current transformer enclosure, meter sockets, and junction box. Net excess generation (NEG) is credited at the utility's retail rate on the customer's next bill. If there is any remaining NEG on April 30 of each year, it is surrendered to the utility without customer compensation. Meter aggregation is provided at a customer's request and is limited to 100 kW per customer.

Utilities are not permitted to require customers to comply with additional safety or performance standards, and they are not allowed to charge additional standby, capacity, interconnection or other fees without approval from the Washington Utilities and Transportation Commission.

CHP Eligibility Requirements

Both fossil-fueled and renewably-fueled CHP systems are eligible for net-metering.